Metal-polyphenol network-mediated high internal phase Pickering emulsion stabilized by coconut protein complex particles: Interfacial remodeling behavior, stabilization mechanism, and 3D printing application

As a novel surface modifier and interfacial cross-linker, the potential of metal polyphenol networks (MPNs) in modifying Pickering stabilizers remains unclear. In this work, tannic acid-Fe³⁺ (TA-Fe³⁺) was used to modify coconut protein-pectin complex particles (CP-PE) to improve their emulsifying properties for stabilizing high internal phase Pickering emulsions (HIPPEs). The results showed that the formation of a thick supramolecular network coating on the surface of CP-PE and CP-PE-TA-Fe³⁺ exhibited a larger particle size, lower H₀, and suitable wettability. CP-PE-TA-Fe³⁺ could adsorb and anchor at the oil-water interface more rapidly, forming a spatial barrier with higher viscoelasticity and mechanical properties to resist disturbances from the processing environment. Moreover, CP-PE-TA-Fe³⁺-stabilized HIPPEs exhibited ideal viscoelasticity and excellent physical stability, enabling them to serve as outstanding inks for 3D printing with superior printing adaptability and printing precision (“letter E" 97.60 ± 0.02 % and “flower” 99.82 ± 0.00 %). Our work provided novel insights into improving the emulsifying properties of food-grade Pickering stabilizers and offered valuable information for broadening the potential applications of MPNs in the food industry.